He was apprehended last week for hanging up a poster in an Ikebukuro bookstore without permission from the store. Police have not stated what the poster said, nor have they released the name of the suspect, which is frequently the case when the mental competence of the suspect is in doubt.

Video footage from the bookstore showed that the suspect visited the store on one of the same days when the library books were defaced, and that he was wandering around areas of the bookstore where books on the Holocaust were. He has also been seen on security footage from locations where books had been ripped.